Vacuum tube connection



Dec, 24, 1946. E. LABIN ETAL VACUUM TUBE CONNECTION Filed April 20, 1942 m mm w N wh R E Hflo VE. NMB n t p R Y B, B R \w M,

Patented Dec. 24, 1946 NETED STATES TENT ()FFICE VACUUM TUBE CONNECTION corporation of Delaware Application April 20, 1942, Serial No. 439,746

This invention relates to improvements in electron discharge tube circuits, and in particular to such circuits for use at ultra-high frequencies.

It is an object of the invention to provide an improved means for making circuit connections to electron discharge devices for ultrahigh frequency operation.

Another object is to provide an improved pushpull type circuit for such devices.

A further object is to provide an ultra-high frequency circuit for use with an electron discharge tube and permitting eificient operation, good cooling of electrodes, and ready accessibility of the tube.

Other objects and various further features of novelty and invention will hereinafter be pointed out or will become apparent to those skilled in the art from a reading of the following specification in connection with the drawing included herewith. In said drawing Fig. 1 is a partly sectionalized longitudinal elevation of apparatus in accordance with the invention; and

Fig. 2 represents a section taken substantially in the plane 22 of Fig. 1.

It is known that in electron discharge tube construction for operation at ultra-high frequencies, it is of the utmost importance to maintain concentricity of electrode elements within the tube and to reduce the length of lead-in connections to a minimum. Many of these devices are accordingly so designed as to fit directly into co-axial line structures which may be used as resonating means for maintaining the tube in oscillation or for other purposes. Devices of this nature and circuit connections therefor have been shown, for example, in the copending applications for patent of G. Chevigny and E. Labin, Serial No. 427,728 filed January 22, 1942; Serial No. 431,134 filed February 14, 1942; and Serial No. 434,914 filed March 16, 1942. These devices are generally of the external anode type whereby the anode may be better cooled to increase operating efiiciency. Connection to the grid as Well as support thereof is by means of an annular disc-like member passing through the envelope,

1 whereby the concentric transmission line connection may be made directly thereto when desired. The present invention makes possible the use of discharge devices of this nature in a pushpull circuit arrangement wherein highly efiicient. operation is possible due to unique disposition of the circuit elements. Referring particularly to the arrangement shown in Fig. 1, a suitable discharge tube of the above-indicated nature 14 Claims. (Cl. 315-38) includes an anode of the re-entrant type having a substantial portion H thereof extending externally of the device for cooling purposes. The anode is of generally cup-shaped form, and disposed concentrically therein are the grid and cathode electrodes. The grid is physically supported by an annular disc l2 that extends outside the envelope of the tube. Filament connections I3, 14 are provided at the end of the tube remote from the anode. Disc l2, besides serving as a support for the grid electrode, is also a lead-out connection. In the form shown, lead-out I2 is formed with two axially extending annular flanges l5, l6 tapering down for purposes of eiTecting a sealing relation with the insulating portions I1, 18 of device it. As shown more clearly in the cross-sectional view of Fig. 2, the external cooling portion H of the anode includesa number of longitudinally and radially extending spaced surfaces for better heat radiation, as will be clear.

In the arrangement shown, two discharge devices like the one just described are mounted in axial alignment with their anode cooling portions ll adjacent one another. The tubes are held in this position by means of a cylindrical member l9 frictionally engaging the end portions of the anode cooling elements. In order to be able to insert the discharge tube precisely into the mounting member 19, the latter includes clamping means 28 for securely holding the tube, and a bottom seat 2!, whereby the extent to which the tube may be inserted in cylinder 19 may be limited. Cylinder I9 is rigidly connected to a further cylinder 22 so as to form a T joint therewith. It will be noted that when clamping means 29 is viewed with cylinder is, a confining passage is defined about the anode cooling elements, said passage being substantially coextensive therewith. As a result. very effective cooling of the two discharge tubes supported by cylinder 19 may be obtained when a cooling medium is introduced into or sucked through pipe 22. In

the form shown, pipe 22 is mounted on a platform 23 spaced from the chassis 24 of the apparatus by means of insulating pedestals 25.

The push-pull oscillator arrangement shown is of the type wherein one resonant condition is made to occur in a circuit including a grid-togrid and an anode-to-anode connection and input circuitresonance is made to occur in the cathodeto-grid circuits of the respective tubes- The first of these resonating circuits comprises a large generally cylindrical member 21 substantially enclosing both the discharge tubes co-axially. Member 25? is galvanically connected to the grids of these tubes by annular adapter means 28 fixed as by clamping to the disc-shaped lead-out E2 of each discharge tube. Adapter 28 in the form shown makes galvanic connection with cylinder by means of a number of conductive fingers extending radially outward into wiping frictional engagement with the inner surface of cylinder The grid-to-grid resonating circuit thus substantially comprises the inductance of the portions of the inner surface of cylinder 21 intermediate the fingers 29 associated with each discharge device, together with the inherent capacity between grid and anode elements of each tube, as will be clear.

As above indicated, input tuning for each discharge tube is accomplished between cathode and grid electrodes. Preferably, the filaments of the discharge tubes are of the double-helix type wherein grounding connection is made to the mid-point, and heater supply is furnished at the free ends of the helixes. Connections to these free ends are made by leads 3%, 3i and to the mid-point by leads 32. In the form shown, the leads 39, ii are brought outside the apparatus by means of a large by-pass-condenser arrangement whereby radio frequency voltages are kept within the oscillator assembly. In the form shown, this by-pass-condenser arrangement comprises two large plates 33, 35c separated from each other by a thin sheet of insulating material, such as mica. Heater supply is made directly to these plates by connections to terminal bolts 35, 31. The lay-passing arrangement comprising plates 33 and 3d separated by the mica sheet 35 is supported in insulated relation within a conductive cylinder 38 by means of blocks 34' and mica sheets 35'. This arrangement maintains the leads iii 3!, 32 at the same radio frequency potential and thus fixes the potential of the mid-point of the filaments.

An extension 2? of cylinder 2'! concentrically surrounds the above described filament lead-out arrangement. Cylinders 27 and 38 are galvanically joined at their left ends. Additional galvanic association between cylinders 2's" and 38 is made by means of an annular connecting link 3:) adjustably slidable, as by means of a push rod 39', longitudinally of the filament lead-out bypass-condenser assembly. In the form shown, cylinders and 2? are electrically associated by a capacitance formed between radially extending flanges 33, d! integral with cylinders 21 and 2?. For a rigid and accurate control of the spacing and alignment of cylinders 12'! and 21', an annular disc d2 of hard molded dielectric material is clamped between the flanges il. The grid-to-cathode oscillating circuit for each discharge device thus substantially comprises the capacitance between flanges 8, 4! and the inductance of the various leads-out in addition to that of the portions of cylinders 27 and 27' be tween adapter 23 and sliding contact 36, as will be clear. As in the case of the anode support 22, cylinder 2'? is rigidly supported above chassis by'means of pedestals 43 of insulating material and the end cylinders it? are likewise supported by such insulating pedestals 4 Ease and accessibility for replacement and adjustment of the discharge tubes within resonating cylinder 2'! form a further feature of the invention. In the form shown, cylinder 21 is formed in two parts of generally semi-circular cross-section, one of which parts is fixedly mounted to the chassis in the above-described manner and the other of which 15 is hinged to the first part by means it fixed to the outer surface thereof. Locking means for securing cover 15 with respect to the fixed part of cylinder 27 comprises a bayonet-type locking plate 6? slida'ole longitudinally as permitted by slots 43 therein into locking or unlocking position. When in locked position, further security is obtained by means of a number of clamping screws which may be provided with knurled edges for manual operation. It is thus possible to obtain complete access to both tubes by effectively removing hall of the enclosing cylinder In accordance with a further feature oi the invention, clamping device it permits the ready removability and adjustment of the discharge devices with respect to the above-described circuit. Device 26 in the form shown comprises an annular collar 58 threaded on the inside and engageable in this manner with a portion of cylinder l9. ioward the end of cylinder it at which collar 53 is threadingly engageable, cylinder i9 is longitudinally split preferably along diametrically opposite lines, thus forming two semi-circular sections. One of these sections Si is transversely cut oil from the rest of cylinder l9 and hingedly related thereto as about a pintle 52. Thus, when collar 58 is removed by unscrewing, portion 5! of cylinder IQ may be swung into upward position, and the discharge tube may be readily removed. Collar preferably includes a conical surface 53 engsgeable with a corresponding conical surface on the end of cylinder it whereby when collar is turned into tightening position, the hinged portion of cylinder i9 will be forced to engage the outer portions of the cooling surfaces oi the discharge tube anode. When it is desired merely to adjust the axial disposition of a discharge tuoe with respect to cylinder IS), a slight release of collar 56 by unscrewing will loosen the grip of the semicircular sections of cylinder it on cooling surfaces ii and thus, permit this adjustment, as will be clear.

It will be seen that the structure described permits a highly efiicient connection of two discharge tubes in push-pull for operation at elevated frequencies. By means of this structure, all radio frequency currents are assuredly maintained within the structure, thus making for a minimum degree of losses. Output connection to the arrangement may be made through a generally oval aperture 54 in the surface of cylinder 2'! to permit a U-type inductive coupling 55 to the anode circuits. It is particularly to be pointed out that the arrangement for mounting the two discharge tubes comprising cylinder 69 and clamping arrangement 29 requires but little increase in overall diameter of the cooling elements II of the discharge devices and, accordingly, introduces substantially no deleterious effects in operation of the arrangement. It is further to be noted that the cooling stream of air or other coolant supplied through cylinder 22 is forced to take a path covering substantially the entire surface of every cooling member for the anodes of the discharge devices. Upon discharge of the coolant adjacent the base of the anode itself, this cooling medium is symmetrically directed so as effectively to cool other portions of the circuit, such as adapters 23, and hence the grid electrodes.

While the above invention has been described in detail in particular connection with the preferred forms illustrated, it is to be understood that many modifications, additions and omissions may be made fully within its scope, as defined by the appended claims.

What is claimed is:

l. A cooling arrangement for simultaneously cooling an electrode of each of two electron discharge devices, each said electrode having a heat conducting portion extending externally of each said device, each said portion being generally cylindrical and including radially extending cooling surfaces, said arrangement comprising a hollow cylindrical member mechanically engaging said Cooling surfaces of one said discharge device at one end of said member and said cooling surfaces of the other said dischar e device at the other end of said member, and a tubular connection to said member between said portions.

2. A device for use at ultra-high frequencies for making connection to and cooling a generally cylindrical electrode lead-out on each of two electron discharge devices, each said lead-out including a plurality of longitudinally and radially extending cooling surfaces, said device comprising a, hollow cylindrical member mechanically engaging the outer edges of said cooling surfaces on both said discharge devices, a tubular connection to said cylindrical member extending generally radially therefrom and communicating with the inside of said member.

3. An ultra-high frequency push-pull electron discharge tube circuit for use with two such tubes each having a ring-type grid electrode lead-out and an anode having an external generally cylindrical cooling portion concentric with said lead-out, said circuit including a hollow cylindrical member mechanically engaging both said cooling portions and maintaining said tubes symmetrically disposed in substantially axial alignment, a further cylindrical member of conductive material co-axially disposed with respect to said tubes and galvanically associated with each said lead-out, said further cylindrical member having an aperture therein substantially intermediate said galvanic associations, and a tubular connection to said first-mentioned cylindrical member extending generally radially therefrom through said aperture in spaced relation with respect thereto and in communication with the inside of said first-mentioned cylindrical member.

4. An ultra-high frequency push-pull electron discharge tube circuit for use with two such tubes each having a ring-type grid electrode lead-out and an anode having an external generally cylindrical cooling portion concentric with said leadout, said circuit including a hollow cylindrical member engaging both said cooling portions and maintaining said tubes symmetrically disposed in substantially axial alignment, a further cylindrical member of conductive material co-axially disposed with respect to said tubes and effectively connected to each said lead-out at least in respect to high frequencies, said further cylindrical member having an aperture therein substantially intermediate said effective connections, and a tubular connection to said first-mentioned cylindrical member extending generally radially therefrom through said aperture in spaced relation with respect thereto and in communication with the inside of said first-mentioned cylindrical member.

5. A mounting arrangement for an ultra-high frequency electron discharge device having an electrode with a heat-conducting portion extending externally of said device, said heat-conducting portion being generally cylindrical and ineluding radially and longitudinally extending cooling surfaces, said arrangement comprising hollow cylindrical member frictionally engaging said cooling surfaces and extending longitudinally therebeyond.

6. An arrangement according to claim 5 wherein said hollow cylindrical member includes annular clamping means at the end thereof about said cooling surfaces, whereby said discharge device may be adjustably related with respect to said mounting arrangement.

7. A push-pull arrangement according to claim 4 for use with discharge devices including filaments with lead-out conductors from the midpoints thereof, and wherein said further cylindrical member includes a portion extending beyond said galvanic associations, further comprising a generally tubular member at least partially within said further cylindrical member, and disposed co-axially with respect thereto and with respect to said discharge devices and adaptable for galvanic connection to one said lead-out conductor, and longitudinally slidable tuning means electrically associating said extended portion of said further cylindrical member and said tubular member.

8. A push-pull arrangement according to claim 4-.for use with discharge devices including filaments with lead-out conductors from the midpoints thereof, and wherein said further cylindrical member includes a portion extending beyond said galvanic associations, further comprising a, generally tubular member at least partially within said further cylindrical member, and disposed co-axially with respect thereto and with respect to said discharge devices and adaptable for galvanic connection to one said leadout conductor, and longitudinally slidable tuning means electrically associating said extended portion of said further cylindrical member and said tubular member, said extended portion of said further cylindrical member including an nnular discontinuity therein and a section of dielectric material at said discontinuity whereby said discontinuity forms a capacitance.

9. A circuit according to claim 4 wherein said further cylindrical member includes two pieces of generally semi-circular cross-section and looking means mounted external of said pieces for holding the same in locked relation.

10. Tuning means for a push-pull amplifier comprising two electron discharge tubes each having a cathode, a grid, and an anode, said tuning means including cylindrical conductive means galvanically connecting said anodes, further cylindrical conductive means galvanicall connecting said grids, both said cylindrical conductive means being co-axial, and means external of said cylindrical conductive means for tuning the grids and cathodes, comprising a first tuning means for the grid and cathode of one of said tubes, and a second tuning means for the grid and cathode of the other of said tubes.

11. Push-pull amplifier tuning means comprising two electron discharge tubes each having a cathode, a. grid, and an anode, cylindrical conducting means galvanically coupling said grids together and said anodes together and forming with the interelectrode capacities between said grids and anodes a resonant circuit, and separate tuning means external of said cylindrical conducting means for separately tuning the grid and cathode of each said tubes.

12. A push-pull amplifier circuit comprising two electron discharge tubes each having a cathode, a

grid and an anode, said anodes being connected to each other, a hollow tube connecting said grids with one another, a first concentric line, means for directly connecting the inner conductor of said concentric line to the cathode of one tube, means for capacitatively coupling the outer conductor of said concentric line to one end of said hollow tube, a second concentric line, means for directly connecting the inner conductor of said second concentric line to the cathode of the other tube, and means for capacitatively coupling the outer conductor of said second concentric line to the other end of said hollow tube.

13. The combination according to claim 12, in which said concentric lines are coaxial with said hollow tube and the outer conductors of said concentric lines are of substantially the same diameter as said hollow tube.

14. A push-pull amplifier circuit comprising two electron discharge tubes each having a cathode, a grid and an anode, said anodes being connected to each other, a hollow tube connecting said grids with one another and provided with flanges at its outer ends, a first concentric line including an outer cylindrical conductor having a flanged end in juxtaposition to and insulated from one flanged end of said hollow tube and an inner conductor connected to the cathode of the other tube.

EMILE LABIN. ROSS B. HOFFMAN. 

